For a few years already, the i915 DRM driver has exposed a way for tests to retrieve the CRC of frames from different places in the graphics pipeline. Here is an example: https://cgit.freedesktop.org/drm/igt-gpu-tools/tree/tests/kms_plane.c

For some of the tests in autotest that make use of frame CRCs with Chamelium, it may make sense to extend them to also run on internal connectors on machines that contain such capability.

Since 4.10, there's a common debugfs ABI for all DRM drivers to expose this to userspace for testing purposes, and it's scheduled that 4.11 will include an implementation for eDP connectors, already tested on veyron.